Cyclopalladated arylsulfides and sulfoxides: Synthesis, characterization and reactivity toward m-chloroperbenzoic acid

Palladium-Catalyzed C–H Alkenylation of Arenes Using Thioethers as Directing Groups

“…Since the arylthioethers with electron-withdrawing substituents showed relatively less reactivity (3gaÀ3ia, 3jc), the intermediate A is possibly formed through an electrophilic palladation process. 14 However, the proton abstract mechanism 15 can not be fully excluded at the moment. After that, the insertion of alkenes affords the carbopalladation intermediate B, which undergoes the β-hydrogen elimination to produce the alkenylated benzyl thioethers and liberate the species HPdOAc.…”

“…Since the arylthioethers with electron-withdrawing substituents showed relatively less reactivity ( 3ga – 3ia , 3jc ), the intermediate A is possibly formed through an electrophilic palladation process . However, the proton abstract mechanism can not be fully excluded at the moment.…”

Reactions of m-chloroperoxybenzoic acid with dimeric cyclopalladated complexes derived from 2-phenyl-2-oxazolines

“…Complexes of type 2 were previously described in reactions of dimeric dichloro-bridged CPCs with various oxidants including m-CPBA; they are one of the two types of oxygen-insertion products reported in these studies [38,47,49,50,54]. It appears that type 2 complexes are relatively unstable, especially during chromatographic purification, and gradually produce the corresponding compounds of type 4 as well as, presumably, PdCl 2 .…”

“…However, in spite of the number of studies focused on reactions of CPCs with m-CPBA, only a few rather similar types of palladacycles have been tested: (1) dinuclear complexes of the CN type derived from azoarenes ( Fig. 1, type A) [36,44,45], (2) mononuclear complexes based on azoarenes and having an additional cyclopentadienyl ligand (B) [20,39], (3) mononuclear complexes based on azoarenes with an SR (C) [40][41][42][43] or other chelating substituent (D) [34,35], (4) dinuclear complexes of the CS type obtained from dibenzyl sulfide, benzyl phenyl sulfide and benzyl phenyl sulfoxide (E) [38] and (5) mononuclear complexes derived from 2-(dimethylamino)methylnaphthalene (F) [47]. In this paper, we report our data for the reactions of m-CPBA with dimeric dichloro-and diacetato-bridged CPCs derived from 2-phenyl-2-oxazolines.…”

“…Oxygen insertion into the C-Pd bond of cyclopalladated complexes can be accomplished by any of the following reagents: m-chloroperoxybenzoic acid (m-CPBA) (used alone [34][35][36][37][38][39][40][41][42][43][44][45][46] or with an iron(III) porphyrin catalyst [37]), other peroxy acids [40], t-BuOOH (used alone [47][48][49][50] or with a catalyst [34,35,[47][48][49][50][51][52]), hydrogen peroxide in the presence of an iron(III) porphyrin catalyst [53], pentafluoroiodosylbenzene C 6 F 5 IO (alone [37,52], in a combination with t-BuOOH [37,52] or in the presence of an iron(III) porphyrin catalyst [37,52]), iodosylbenzene C 6 H 5 IO [54], [di(benzoyloxy)iodo]benzene PhI(O 2 CPh) 2 [55] and the molybdenum peroxide MoO(O 2 ) 2 ÁHMPAÁH 2 O (HMPA = hexamethylphosphoric triamide) [14,56]. The mechanisms involved in these transformations appear to be different [5]; however, in all cases, the C-Pd bond is transformed into the C-O-Pd moiety.…”